Polymers of vinyl (perfluorocyclopropane)

ABSTRACT

Disclosed herein are polymers made by free radically polymerizing the novel compound vinyl(perfluorocyclopropane), and optionally other monomers to form copolymers. The repeat unit formed by vinyl(perfluorocyclopropane) contains an olefinic bond, making it particularly useful as a grafting and/or crosslinking site.

This is a divisional application of Ser. No. 08/312,723, filed on Sep.27, 1994, now U.S. Pat. No. 5,420,367.

FIELD OF THE INVENTION

This invention concerns polymers containing repeat units derived fromthe free radical polymerization of the novel compoundvinyl(perfluorocyclopropane).

TECHNICAL BACKGROUND

Fluorinated polymers are important items of commerce, being particularlyuseful in situations where heat and/or chemical resistance are required,for example in films and coatings. Therefore new fluorinated polymersand/or technology for usefully modifying "known" fluorinated polymersare constantly being sought.

Unfluorinated vinylcyclopropane and it polymers has been described in F.Sanda, et al., Macromolecules, vol. 25, p. 6719-6721 (1992); ibid., vol.26, p. 1818-124 (1993); ibid., vol. 26, p. 5748-5754 (1993).

SUMMARY OF THE INVENTION

This invention concerns-a polymer, comprising, the repeat unit --CF₂ CF₂CF=CHCH₂ --(I).

This invention also concerns a compound of the formula ##STR1## whereinQ is --CH₂ CH₂ X or --CH=CH₂, wherein X is Cl, Br or I. It is preferredif X is Br.

The polymers described herein are useful for films and coatings, and therepeat unit formed by free radical polymerization of vinyl(perfluorocyclopropane) (VPCP, also sometimes calledvinylpentafluorocyclopropane) is particularly useful as a crosslinkingor grafting site for such polymers.

DETAILS OF THE INVENTION

The essential monomer used herein is VPCP. It is made by the proceduresshown in Examples 1 and 2. It can be free radically polymerized bycontact with free radicals using for instance common free radicalinitiators, including, but not limited to, bis(perfluoropropionyl)peroxide, benzoyl peroxide, potassium persulfate andpersulfate-bisulfite redox pair.

The polymerizations may be carried out in any conventional way, forexample, solution, aqueous dispersion or emulsion, organic emulsion orneat. They may be done batch, continuous and semibatch, see, forinstance, polymerization methods described in H. Mark, et al., Ed.,Encyclopedia of Polymer Science and Engineering, vol. 16, John Wiley &Sons, New York, 1989, p. 577-648. Suitable organic solvents ordispersants include halocarbons such as1,1,2-trichloro-1,2,2-trifluorethane (CFC113), perfluoroethers such asperfluorotetrahydrofuran, and perfluorosulfides.

The VPCP may be polymerized by itself to form a homopolymer, or may becopolymerized with other monomers to form copolymers. Suitablecomonomers include tetrafluoroethylene,perfluoro(2,2-dimethyl-1,3-dioxole), perfluoro(propyl vinyl ether),perfluoro(methyl vinyl ether), chlorotrifluoroethylene, vinylidenefluoride, hexafluoropropylene, and vinyl fluoride. Preferred comonomersare tetrafluoroethylene, perfluoro(2,2-dimethyl-1,3-dioxole), andperfluoro(alkyl vinyl ether), and tetrafluoroethylene is especiallypreferred. Particularly preferred copolymers are elastomeric copolymerscontaining VPCP, hexafluoropropylene, vinylidene fluoride, andoptionally tetrafluoroethylene. By "comprising" herein it is meant thatthe polymer contains the repeat unit derived from VPCP plus any otherrepeat units. Copolymers are preferred polymers of VPCP.

The repeat unit that the VPCP produces by the polymerization is --CF₂CF₂ CF=CHCH₂ --, which contains an olefinic bond. This olefinic bond isreactive towards nucleophiles, and so may react with suitablenucleophiles to form a graft polymer. If a di- or higher functionalitycompound (containing two or more nucleophilic reactive groups) is used,the polymer will be crosslinked. This makes VPCP particularly valuableas a curesite monomer in elastomers, especially those which are(partially) fluorinated and can now be cured through double bonds whichare present or are generated. Such copolymers include those ofvinylidene fluoride and hexafluoropropylene, optionally also containingtetrafluoroethylene, and the copolymer of tetrafluoroethylene andpropylene. Since curesite monomers are often present in elastomers inrelatively low concentrations, in one preferred embodiment the repeatunit from VPCP (I) is about 0.2 to about 5 mole percent of the totalnumber of repeat units present in the polymer.

In DSC determinations, the instrument used was a DuPont DSC 2190, with aheating rate of 20° C./min, and the maximum of the endotherm was takenas-the melting point.

In the Examples, the following abbreviations are used:

DMF--N,N-dimethylformamide

DMSO--dimethylsulfoxide

DSC--differential scanning calorimetry

FC-75--perfluorobutyltetrahydrofuran

PTFE--polytetrafluoroethylene

TGA--thermogravimetric analysis

EXAMPLE 1 Preparation of 2-bromo-1-(pentafluorocyclopropyl)ethane

A 300 mL shaker tube was charged with 65 g of CF₂ =CFCH₂ CH₂ Br and 114g of hexafluoropropylene oxide and heated at 200° C. for 9 hrs. Crudeproduct (80.3 g) was distilled to give 8.6 g of bp 95.6°-106° C.materials and 61.2 g of bp 107° to 111° C. materials which obtained 16%starting material CF₂ =CFCH₂ CH₂ Br. Further distillation on a spinningband gave 41.3 g of pure 2-bromo-1-(pentafluorocyclopropyl (ethane), bp111° to 112° C. ¹⁹ F. NMR: -152.5 (dt, J=197 Hz, J=7.2 Hz, 2F), -157.1(dm, J =197 Hz, 2H), -212.3 (tt, J=21.5 Hz, J=7.1 Hz, 1F). ¹ H NMR: 3.53(t, J=7.1 Hz, 2H), 2.55 (dm, J=21.5 Hz, 2H) .

EXAMPLE 2 Preparation of vinylpentafluorocyclopropane

To a stirred solution of 18.0 g of KOH, 15 mL of ethanol and 20 mL ofwater was slowly added 24.0 g of2-bromo-1-(pentafluorocyclopropyl)ethane at 70° C. During the addition,volatiles were collected in a -78° C. trap. After the addition wascomplete, the reaction mixture was stirred at 70° C. for an additionaltwo hours until collection of all volatiles, which was distilled to give9.1 g of product, bp 30° C. ¹⁹ F NMR: -152.3 (dt, J =195.4 Hz, J=9.8 Hz,2F), -156.0 (dm, J=195.6 Hz, 2F), -210.7 (t, J=7.7 Hz, 1F) . ¹ H NMR:5.86-5.73 (m, 2H), 5.70-5.65 (m, 1H).

EXAMPLE 3 Homopolymerization of vinylpentafluorocyclopropane

A 25 mL glass ampul fitted with a PTFE coated stir bar was charged with0.3 mL of 5% of bis(perfluoropropionyl) peroxide in1,1,2-trichlorotrifluoroethane and 1.1 g of the title compound. Theampul was sealed and cooled in a liquid nitrogen bath. After beingevacuated and purged with N₂ alternately six-times, contents of thesealed ampul were stirred at 40° C. for 4 hours. The white solids werewashed with acetone and dried under vacuum at 125° C. to give 1.1 g ofpolymer.

The IR spectrum of this polymer showed an absorption at 1719 cm⁻¹ whichcould be attributed to double bonds in the polymer.

This polymer was insoluble in acetone, ethyl acetate, tetrahydrofuran,acetonitrile, DMSO, DMF, hexafluorobenzene and FC-75. The polymer had amelting point of 130° C. by DSC (second heat). By TGA the polymer showed10% weight loss temperatures of about 400° C. in nitrogen and 375° C. inair when heated at 20° C./minute.

EXAMPLE 4 Comopolymerization of vinylpentafluorocyclopropane withperfluoropropyl vinyl ether (PPVE)

A 25 mL glass ampul fitted with a PTFE coated stir bar was charged with0.3 mL of 5% of bis(perfluoropropionyl) peroxide in1,1,2-trichlorotrifluoroethane and 1.1 g of the title compound and 1.0 gof PPVE. The ampul was sealed and cooled in a liquid nitrogen bath.After being evacuated and purged with N₂ alternately six times, contentsof the sealed ampul were stirred at 40° C. for 18 hours. The whitesolids were washed with CFC113 and dried under vacuum at 125° C. to give0.9 g of polymer.

This polymer was insoluble in acetone, ethyl acetate, tetrahydrofuran,acetonitrile, DMSO, DMF, hexafluorobenzene and FC-75. The polymer had amelting point of 131° C. by DSC (second heat). By TGA the polymer showed10% weight loss temperatures of about 405° C. in nitrogen and 370° C. inair when heated at 20° C./minute.

EXAMPLE 5 Comopolymerization of vinylpentafluorocyclopropaneperfluoro-2,2-dimethyl-1,3-dioxole (PDD)

A 25 mL glass ampul fitted with a PTFE coated stir bar was charged with0.3 mL of 5% of bis(perfluoropropionyl) peroxide in1,1,2-trichlorotrifluoroethane and 1.0 g of the title compound and 1.0 gof PDD. The ampul was sealed and cooled in a liquid nitrogen bath. Afterbeing evacuated and purged with N₂ alternately six times, contents ofthe sealed ampul were stirred at 40° C. for 18 hours. The white solidswere washed with CFC113 and dried under vacuum at 125° C. to give 0.9 gof polymer. This polymer was insoluble in acetone, ethyl acetate,tetrahydrofuran, acetonitrile, DMSO, DMF, hexafluorobenzene and FC-75.The polymer had a melting point of 127.5° C. by DSC (second heat). ByTGA the polymer showed 10% weight loss temperatures of about 395° C. innitrogen and 355° C. in air when heated at 20° C./minute.

EXAMPLE 6 Comopolymerization of vinylpentafluorocyclopropane withchlorotrifluoroethylene(GTFE)

A 25 mL glass ampul fitted with a PTFE coated stir bar was charged with0.3 mL of 5% of bis (perfluoropropionyl) peroxide in1,1,2-trichlorotrifluoroethane, 1.0 g of the title compound, 1.0 g ofCTFE and 2 mL of CFC113. The ampul was sealed and cooled in a liquidnitrogen bath. After being evacuated and purged with N₂ alternately sixtimes, contents of the sealed ampul were stirred at 40° C. for 72 hours.The white solids were filtered, washed with CFC113 and dried undervacuum at 125° C. to give 0.15 g of polymer.

This polymer was insoluble in acetone, ethyl acetate, tetrahydrofuran,acetonitrile, DMSO, DMF, hexafluorobenzene and FC-75. The polymer had amelting point of 127° C. by DSC (second heat). By TGA the polymer showed10% weight loss temperatures of about 400° C. in nitrogen and 155° C. inair when heated at 20° C./minute.

What is claimed is:
 1. A polymer, comprising, the repeat unit --CF₂ CF₂CF=CHCH₂ -- (I).
 2. The polymer as recited in claim 1 which is acopolymer.
 3. The polymer as recited in claim 2 wherein a comonomer isone or more of tetrafluoroethylene, perfluoro(2,2-dimethyl-1,3-dioxole),perfluoro(alkyl vinyl ether), or chlorotrifluoroethylene.
 4. The polymeras recited in claim 3 wherein a comonomer is one or more oftetrafluoroethylene, perfluoro (2,2-dimethyl-1,3-dioxole),perfluoro(propyl vinyl ether), or perfluoro(methyl vinyl ether).
 5. Thepolymer as recited in claim 4 wherein a comonomer istetrafluoroethylene.
 6. The polymer as recited in claim 1 wherein (I) isabout 0.2 to about 5 mole percent of repeat units in said polymer. 7.The polymer as recited in claim 2 which is elastomeric, and whereincomonomers are hexafluoropropylene, vinylidene fluoride, and optionallytetrafluoroethylene.
 8. The polymer as recited in claim 7 wherein acomonomer is tetrafluoroethylene.
 9. The polymer as recited in claim 7wherein (I) is about 0.2 to about 5 mole percent of repeat units in saidpolymer.